RicodJour wrote:

Tim Fischer wrote:

wrote in message


Did you get a reputable brand or one of those Chinese jobbers?-Jitney

I have "one of those Chinese jobbers" and it's very accurate -- IF you
calibrate it. The instructions included steps on how to calibrate the
device. It's a pain, but once done, the level is accurate to about a
quarter inch over 30 feet, which is what the specs for the device say... I
can't get a water level even close to that level of accurace but it could be
my technique...


Must be. Water levels are very easy to use and very accurate. Can you
describe what you do and what you use?

R


Water levels while easy to understand in principal, suffer from thermal
expansion effects if the water throughout ther length isn't kept at the
same temperature. Liquids expand a lot more than most solids do.

Water at around 75 F changes density about -150*10^-6 per degree F with
increasing temperature.

If you are using a simple water level made of clear tubing with the ends
raised about 6 feet above the lowest point of that tubing, and sunlight
heats one leg 10 F warmer than the other, there will be about an eight
of an inch of error. The water level in the warmer leg will be higher
than that in the other one.

Not much to worry about in most applications, but worth keeping in mind
if SWMBO absalutely positively wants those pictures of your grandkids
hung at exactly the same height. G

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."